Each day more than 200,000 United States Postal Service (USPS) carriers deliver mail to approximately 100 million individual domestic addresses. Mail generally consists of three broad types of items, namely letters, flat mail that is larger than letter mail, and parcels. Before a carrier begins to walk through or drive through his or her delivery route, it is the carrier's responsibility to put all of this mail into an appropriate sequence for efficient delivery.
Under the present USPS procedure, the carrier assembles at least three sequenced stacks of mail, including letters, flats (including enveloped and non-enveloped magazines), and parcels. The carrier may also have one or more additional sequenced stacks, e.g., pre-sorted mass-mail items to be delivered to many or all of the stops on the delivery route. Thus, at each delivery stop the carrier selects the items for that address from each of the various stacks and puts them all into the postal patron's mailbox. This sorting and shuffling through various stacks of mail is time consuming, inefficient, and consequently expensive to the USPS.
Preliminary tests by the USPS indicate significant potential savings in carrier delivery time if all of the mail pieces for each stop are consolidated into a single package before the carrier begins delivery activities. However, with current mail sorting procedures and the mail-casing equipment now available to the carriers, the additional time required for the carrier to pre-consolidate the mail into individual packages essentially negates the potential savings in delivery time.
More efficient procedures and equipment can be deployed within the post office to make the operation more efficient, thus saving substantial amounts of time and money, by making use of a different sorting system and method as described herein. The current mail case into which the carrier pre-sequences the mail is shown in FIG. 1 as mail case 20. Mail case 20 is not ergonomically well designed to accommodate letters and flats together, nor highly suitable to facilitate expeditious containerizing most or all of each patron's mail for efficient delivery.
Two significant problems have been observed. Dividers 21 between stops in existing USPS mail cases are relatively rigid, and they cannot conveniently be repositioned during a sort. If a particular patron gets an excessive amount of mail on a given day, the carrier removes part or all of it temporarily. The carrier then must reconsolidate that patron's mail at the end of the casing operation. Also, as the slot fills, it becomes increasingly difficult to case additional mail into that slot. A more flexible partition between slots would help to remedy both of these shortcomings.
The slots are generally too small to accommodate flats without folding them over as shown in FIG. 1 (folded flat 22). This folding operation is time-consuming and thus costly, and it tends to fill the slot prematurely. In some cases the mail cannot be folded without incurring damage. In this case it must be handled separately, incurring additional handling time and associated labor cost. Larger slots eliminate some of this additional handling effort, but wastes space.
For efficient delivery, all of the mail for each postal patron should be individually containerized or wrapped. To accomplish this with the existing case 20, the contents from each slot must be removed and packaged one stop at a time. With the existing USPS case design, the time required to package each patron's mail stop-by-stop exceeds the resulting time savings along the delivery route.
The USPS has attempted a system wherein a grocery store-style frame holds a horizontal stack of plastic bags. One bag is torn off the pad and made ready for filling by stretching it open on the frame, while the remaining bags remain on the pad in a closed or completely collapsed (flat) condition. In pulling down the mail from the slots in the case, the postal carrier takes mail from one slot, puts it in a bag, removes the bag from the frame and puts it in a flats tub or letter tray, generally in delivery order. This exposes the next bag on the frame for the mail in the next case slot corresponding to a delivery address. This process makes use of bags to keep mail for a single destination together, but requires several steps and is thus labor intensive. The pull-down process is carried out one destination at a time.